We are continuing high-resolution X-ray diffraction studies of virus structure and concomitant biochemical experiments on assembly in the following directions: (1) refinement of the atomic model of tomato bushy stunt virus (TBSV) (at 2.9 A); (2) building and refinement of an atomic model of turnip crinkle virus (TCV) at 3.2 A and comparison with TBSV; (3) analysis of an 8.0 A map of expanded TBSV; (4) isolation of crystallization of the N-terminal "R-domain" of TBSV; (5) determination of the nucleotide sequence of TCV-RNA; (6) analysis of the pathway in vitro reassembly of TCV; (7) crystallization and initial X-ray analysis of poliovirus.